This study demonstrates a low-temperature Ohmic contact to WSe2 using a van der Waals (vdW) junction between highly p-doped MoS2 (p+-MoS2) and WSe2. p+-MoS2 exhibits a large work function comparable to that of a well-known metal such as Pt. Owing to its layered crystal structure, p+-MoS2 can easily be exfoliated to obtain atomically flat, freshly cleaved surfaces. Moreover, it is stable in air; therefore, this material can be used as an efficient hole-injection contact to a transition metal dichalcogenide semiconductor like WSe2. An h-BN encapsulated WSe2 field effect transistor (FET) was fabricated, having electrical contacts in the form of two flakes of exfoliated p+-MoS2. The fabricated FET demonstrated Ohmic contact behavior under hole doping between room temperature (295 K) and liquid helium temperature (4.2 K). Further, owing to the low contact resistance of the p+-MoS2/p-WSe2 junction, metal-to-insulator transition of WSe2 was observed upon hole doping, as well as quantum oscillation under the application of a magnetic field. On the basis of the Arrhenius plot, a potential barrier height of ∼41 meV at the p+-MoS2/p-WSe2 junction was determined; we infer that this value is limited by the carrier depletion region of p+-MoS2 at the junction. Overall, this appears to indicate potential high performance of the p+-MoS2/WSe2 vdW Ohmic contact.

中文翻译：

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使用 p+-MoS2/WSe2 范德华界面与 WSe2 的低温 p 型欧姆接触

该研究展示了使用高度 p 掺杂的 MoS2 (p+-MoS2) 和 WSe2 之间的范德华 (vdW) 结与 WSe2 的低温欧姆接触。p+-MoS2 表现出与众所周知的金属（如 Pt）相当的大功函数。由于其层状晶体结构，p+-MoS2 可以很容易地剥离以获得原子级平坦、新鲜切割的表面。而且在空气中稳定；因此，这种材料可用作过渡金属二硫属化物半导体（如 WSe2）的有效空穴注入接触。制造了 h-BN 封装的 WSe2 场效应晶体管 (FET)，具有两片剥离 p+-MoS2 薄片形式的电触点。制造的 FET 在室温 (295 K) 和液氦温度 (4.2 K) 之间的空穴掺杂下表现出欧姆接触行为。更多，由于 p+-MoS2/p-WSe2 结的低接触电阻，在空穴掺杂时观察到 WSe2 金属到绝缘体的转变，以及在磁场应用下的量子振荡。根据阿伦尼乌斯图，确定 p+-MoS2/p-WSe2 结处的势垒高度约为 41 meV；我们推断该值受结处 p+-MoS2 载流子耗尽区的限制。总体而言，这似乎表明 p+-MoS2/WSe2 vdW 欧姆接触具有潜在的高性能。我们推断该值受结处 p+-MoS2 载流子耗尽区的限制。总体而言，这似乎表明 p+-MoS2/WSe2 vdW 欧姆接触具有潜在的高性能。我们推断该值受结处 p+-MoS2 载流子耗尽区的限制。总体而言，这似乎表明 p+-MoS2/WSe2 vdW 欧姆接触具有潜在的高性能。